in moist, rich, sandy, or gravelly soils along streams, near springs, 

 or in marshy meadows, where it often forms large, dense patches. 

 In some localities it occurs singly, intermixed with other plants. 

 This plant invariably shuns dry sites. The flowers usually appear 

 during July and August, while the seed ripens in September. 



Because of its great succulence, the species is especially relished 

 by sheep, having a palatability rating of from very good to excellent 

 for that class of livestock and from fair to fairly good for cattle. 

 It also ranks as good forage for deer and elk. However, due to the 

 fact that this butterweed grows exclusively in moist or wet sites, 

 and ordinarily is of limited occurrence, its importance is usually 

 limited to those high-mountain ranges where it is locally abundant 

 on the moister sites. During the spring and early summer porcupines 

 commonly feed along the streams, and readily eat the lush leaves 

 of this species. 



Sampson 1 found that, on the Wallowa National Forest, north- 

 eastern Oregon, the lower portion of the stem is the only part of 

 this plant which sheep will not readily consume up to the first of 

 August, and that the species is one of the most highly relished of 

 the late forage plants of that locality. This investigator noted a 

 rather low seed viability of this species, seed ripened by Septem- 

 ber 5 having germinated 18 percent in 1908 and 26 percent in 1909, 

 the later maturing seed having a notably lower viability. 



Arrowleaf butterweed is confused sometimes with sawtooth but- 

 terweed ($. serra), as the two plants often occur on similar sites, 

 are of about the same size, and both have large, leafy stems. Dif- 

 ferences in leaf form are their chief distinguishing feature, the 

 leaves of arrowleaf butterweed being definitely wedge- or arrow- 

 shaped, in contrast to those of sawtooth butterweed, which are 

 lance- or egg-shaped, and taper at the base to such an extent as to 

 obscure the leafstalk. The leaf margins of both plants are toothed. 



1 Sampson. A. W. IMPORTANT RANGE PLANTS : THEIR LIFE HISTORY AND FORAGE VALUE. 

 U. S. Dept. Agr. Bull. 545, 63 pp., illus. 1917. 



